Two people were injured when a lorry collided with a Luas at Cheeverstown just after 6am.
Five units of Dublin Fire Brigade and an ambulance attended the scene.
A spokesperson confirmed the two injured people had been taken to hospital as a precautionary measure but their injuries are not thought to be life threatening.
The road was then blocked by Gardai and the Red Line service between Belgard and Saggart was suspended until 9am.
The Scania lorry was driving on the main R136 road towards Tallaght when it collided with the Luas crossing its path alongside the Katherine Tynan Road.
The moving Luas dragged the lorry into a traffic island where it was wedged between the tram and the railings on the island.
The driver’s side of the lorry was damaged as was the side of the Luas.